Method of corner construction



March 15, 1949. H. A. KAUFMANN 2,464,514

METHOD OF CORNER CONSTRUCTION- Filed May 25, 1.945

. HARRY A. KAUFMANN INVENTOR FIG. 5 I 4 v W ATTORNEY Patented Mar. 15,1949 METHOD OF CORNER CONSTRUCTION Harry A. Kaufmann, Detroit, Mich.,assignor to The Kaufmann Corporation, Detroit, Mich., a corporation ofMichigan Application May 25, 1945, Serial No. 595,797 r This inventionrefers to interconnecting or aligning means, and a method of formingsame, for a construction including a pair of abutting members, and itrefers particularly to such means and method for screen or window sashconstruction.

In providing means for fastening together abuting members such as windowand screen sash elements, there is presented a large number of problems.Primarily, of course, it is essential that the elements being heldtogether are held firmly against movement with respect to each other. Itis also desirable, particularly in window and screen sash construction,that the holding means be contained internally within the sash elements,in order not to mar or interrupt the smoothness of the externalappearance of the sash elements. It is also desirable that the fasteningmeans be capable of economical fabricacation and rapid and easyinstallation.

These problems have in the trade been met in a variety of ways, of whicha general type is the provision of a connecting member made from sheetstock internally engaging hollow abutting sash elements. This generalapproach is used both for corner constructions and for the connection ofseparate elements placed lineally together, as sometimes happens where,for one reason or another, the sash along one side of a window or screenpanel is made of more than one piece. A variety of ways have beenproposed for holding these connecting members in position, which waysinclude positive holding by screws, bolts or by embossings. Examples ofthese constructions are illustrated in my Patents Nos. 2,291,726 and2,292,273.

These and other known constructions, however, are not entirelysatisfactory because they usually present an unsightly appearance due tothe embossings or screws used to hold the corner element in place, andbecause their holding is not sufiiciently positive to prevent at least asmall amount of relative movement between the abutting elements. Sinceeven a very small amount of such relative movement is suflicient toprovide a large degree of flexibility in a construction such as a sash,it is desirable to reduce such'relative movement to its absoluteminimum.

Further, the fabrication of the corner elements and the sash members byindependent processes often creates aslight amount of size variationand/or discrepancy which; even though small, is sufilcient to permit alarge amount of undesirable flexibility in the finished sash. It isfurther desirable in someinstances to useextruded sash 102 ivendiecasting die.

2 Claims. (Cl. 29148) 2 sections, and these are particularly difiicultto handle with the usual type of plate or angle corner elements. Wheredie cast connecting members are used, the precise fitting of thecontactfiijjglllg parts is difficult, if not impossible. Generalexperience shows that hollow or formed sections, whether extruded orrolled nearly always have at least slight variations that can never beuniversally fitted by corner members made from a These dies areexpensive and cannot be easily or rapidly varied or corrected to meetchanging conditions of construction or variations in dimensions. Hence,there is desired a method by which the connecting mem- 3 bers areconstantly varied appropriately to variag acorners and ends together.While this does effect a bond, it is not only expensive but the heat ofthe welding operation in many cases injures or destroys the crystallinecharacteristics of the metal being used. Particularly with sections'smwhich are heat-treated to a particular desirable degree of hardnessand stiffness, the heat of the welding operation destroys the efiects ofthe heat-treating and requires that the parts be rehardened. This, ofcourse, imparts further ex- 30iipense to the entire fabricationprocedure.

Welding is further expensive in that when the operation is completedthere is a certain amount of work required to clean up, polish andsometimes grind a corner to give it a good appearance.

Particularly, if the sections have external grooves or channels, thesewill be distorted and/ or partly filled by the welding procedure andmust be ground out in order to restore the sections comprising thecorner to their original appearance.

,All of this is time consuming and accordingly expensive.

It is therefore desirable that there be provided means and a methodparticularly adaptable to hollow extruded sections for binding theirabut 5 .ting ends firmly together, whether they be corners or otherwise,which will hold the parts firmly which can be made quickly and cheaply,which will be applicable to aluminum sections if desired, but notlimited thereto, and when so used will not destroy the efiects of theheat treating of the aluminum and which will not discolor the corner ordis-figure it by the presence of positive fastening means such as screwsor 'embossings.

Accordingly, the principal object of my inven .tion is to provide amethod, and specific means for practicing same, for binding togetherabutting elements of a metal sash.

A further object of my invention is to provide a method, and means forpracticing the same, for binding abutting elements together which willdo so firmly and which will reduce play between said elements to aminimum.

A further object of my invention is to provide a method, and means forpracticing same, for binding abutting elements together as aforesaidwhich can be eifected rapidly and cheaply.

A further object of my invention is to provide a method, and means forpracticing same, for binding said elements together as. aforesaid whichvwill be applicable, though not limited, to an ex-- truded section madefrom aluminum, or aluminum alloy.

A further object of my invention is to provide a method, and means forpracticing same, for binding metal sash elements together as aforesaidwhich will not alter the crystalline characteristics of adjacentportions of the sash elements.

A further object of my invention is to provide a method, and means forpracticing same, for binding sash elements together as aforesaid whichis free from all things which might disfigure. or otherwise affect theexternal appearance of the sash section.

Other objects and purposes of, my invention will be apparent to thosewho are acquainted with processes and equipment of this sort upon anexamination of the accompanyin drawings and reading of the followingspecifications. In the drawings:

Fig. 1 represents, a side, partially broken view of means used inpreparing asash holding element.

Fig. 2 is a section taken on line.IIII of Fig. 1..

Fig. 3 is a partially broken view showing a corner construction whereinthe holding element is partially inserted into the sash members.

Fig. 4 illustrates in partial section similar to Fig. 1 a modificationof my method.

Fig. 5 illustrates in partial section similar to Fig. 1 a differentapplication of my method.

Fig. 6 illustrates in partial section. similar to Fig. 1- a furtherapplication, of my method.

In effecting the objects'andipurposes. above out.- lined I have, after alarge amount of experimentation, discovered a satisfactory procedurewhich, in addition to solving the screen, construction, is capable ofwide applicability to a variety of other similar problems. Since mymethod is best understood with reference to a particular situation andto particular apparatus for practicing the method, attention is directedto the accompanying draw ings and to the specific examples of myprocess. therein illustrated.

Looking first at Figs. 1, 2 and 3, it is desirable to bond the cornersof a screen sash comprising elements having the cross-section generallyindicated at I in Fig. 2, which elements, for the purposes of thisexample, may be assumed to be of an extruded aluminum alloy having amelting point of approximately 1,025 F. There will first be provided aplate 2 having a pair of suitably placed clamps 3 and 4. A pair of moldsections- 5 and 6 are cut from the same stock as will be used for thefinished screen sash. Thesev may usually, but not necessarily, be takenfrom scrap, suchas cut-off ends which are too. short for use as sashmembers. These sections are suitably mitered and placed together at ltoform a: duplicate of the desired corner. corner is contemplated, but itwill be evident that a corner of any other angle or even lineal abut-Here a right angular ment (Figs. 5 and 6) may be provided by slightmodification of the procedure described following.

The sections 5 and G are placed under the clamps 3 and 4, held as shownand suitably preheated. There is then provided a quantity of metal whichwill melt at a temperature substantially lower than the melting point ofthe metal comprising the sections which are to be bonded together andfrom which the mold sections 5 and 6 are taken. This metal when cooledand hardened should preferably also be somewhat softer than the metalcomprising the sections which are to be bonded together. However, thislatter, while advantageous in. securing rapid and accurate subsequentassembly, is not essential. For this purpose any conventional diecastingmetal will be suitable. By way of example I have found particularlyadvantageous a zinc alloy known to the trade as Kirksite which ismanufactured by Morris P. Kirk and Son, Inc. of Los Angeles, California,and which melts at about; 715 F. Thisv metal is. heated sufilciently toplace it. in a fluid state. at a. temperature somewhat over its meltingpoint, in the. case. of. Kirksite from. 80.0. F. to 850 F. and is. thenheld at such tern.- perature for use. A predetermined amount. of such,metal is. poured into the opening 8' within the sections 5 and 6sufficient to fill both of said. sections. a selected distance fromtheir respective abutting ends. The metal immediately flows to fill bothsections to a substantially constantlevel and thus provides an exact:duplicate of the space 8' within the sectionsv 5 and 6 for the. selecteddis'- tance from the abutting ends. The. meniscus. of

' theliquid metal will, when it is. hardened provide a convenient:rounding of each end of: the. corner angle casting. By replacing the.sections. 5 and. 6' frequently with scrap from the current produc:--tion run, the corner element9' thereby formed always conform exactly tothe particular size and shape. of the opening within the sash. sectionsbeing used at any given time. Although. extruded metal. sections willnormally beheld within close size tolerances, this method of forming thecorner connectingv member will provide foreven the variations andidiosyncrasies which do sometimes occur.

As soon as the casting metal is: set; which" will. be a. matter of only.a few moments, the back.- ing plate. 2' is engaged by suitable tongs orhooks; and the entire assembly: shown in Fig. 1 is cool'ed. in anyconvenient manner, such as by dipping into cold water. The mold sections5 and" B are then dumped onto a table where they are pulled apart. andthe corner member 9 separated from them. The mold sections may then beplaced back in their original: position on the plate 2 and the mold is.ready to repeat. thecycle.-

It should. be noted thatl sin'ce the moldisection is. pre-heated, thecastingwill form at a. sizeslightly greater than: the interior openingof the sections. when cold. Whenever on. cooling the casting willvcontract at about the samerate as the. mold, it neednot be ejected untilthe mold, is: substantially cooled. The finished and com-- pletelycooled casting williin: such case be" of such size. as to. be able toenter the central opening of a sash section identical with the moldaudit. will make" an exceedingly tight fit therein.

It: will often be: desirable in theinterest of assuring; a completelytight fit betweenthe: corner angle casting and the sash sections, andpartied-+- larly so when the casting metal used contracts at a. slightlygreater rate than themet-aI of' the members; used for a: mold, toenlargeslightly;

by any convenient means such as with a file, the internal opening withinsaid section. In this way the mold can be made slightly oversize so thatthe finished and cooled corner casting will be of correct size for anextremely tight fit.

It will also often be desirable to apply a few strokes of a file totheinterior of the scraps of sash section used as molds in such a manner asto create a slight taper at theinterior of each part of the mold, asillustrated in somewhat exaggerated form in Fig. 4 wherein the surfacesl and. H represent the interior walls diverging slightly from theposition of the original walls which are indicated by the dotted linesl2 and [3. In this way the corner casting will be slightly tapered andthus will more easily enter into the central opening of the sashsections. This diverging of the walls near the respectively abuttingends of the mold sections will also normally provide the slight oversizementioned above as desirable.

Where one side of the central opening within the sash member is open, asin the W type sections used in the constructions shown in my above namedpatents, this same process may still be used by inserting into the openside a suitable guard or dam and thus converting a part of the internalspace for casting purposes into a closed hollow chamber similar to thesection shown in Fig. 2. The process may similarly be applied where theopening is not a central opening as such but is only a recess,especially an undercut recess, along the sides of the members beingfastened.

In assembling a screen or window sash it will be found that these cornermembers can ordinarily be pushed by hand a part of their length into thecentral opening of the sash, and then will need to be struck a few blowswith a hammer to force them in the rest of the way. This will beespecially true if the castings have been provided with a slight taperas mentioned above. This will insure their being absolutely tight sothat the corner is not likely to come apart accidentally nor will itordinarily have any play.

By selecting the casting metal to be substantially softer than the metalof the sash sections it will be evident that the slightly oversizedportion of the corner casting will yield and conform to the shape andsize of the central opening within the sash section. While it is obviousthat such conforming cannot involve any great changes in shape or sizeof the corner casting there will still be suflicien-t to permit aslightly oversized corner member to be inserted and driven tightly intoplace without scraping, tearing or damaging in any way the parts of thesash sections and particularly the walls of the opening therein.

If a material is used for the corner casting which is harder than thematerial from which the sash sections are made, there will still besecured a mutual adjustment to assure a tight and rigid fit. However, inthis case the material yielding will be the sash section material and,while it may be permitted in some instances, it will normally be lessdesirable than if the yielding is done by the material comprising theconnecting member.

It will be understood that the casting material must melt and becomefully liquid in a temperature range substantially below the melting oreven the softening point of the metal comprising the molds in order toavoid any tendency for the corner member to stick within the mold 6sections. In the-above given example the sash sections aretaken to bemade from aluminum melting at approximately 1,025 F. and there isemployed for the casting metal an alloy melting at approximately 715 F.Any other materials and respectively appropriate temperatures will besuitable providing only the above stated conditions are satisfied. Forexample if the sash sections were made of steel the casting materialcould, if desirable for other reasons, be selected from groups of alloyssuch as the bronzes and/ or the brasses having somewhat higher meltingpoints.

It is obvious that with corner members made in this way the process ofassembling window sash sections will be extremely fast, and that thetime, equipment and labor ordinarily involved in setting screws,eifecting embossings or engaging other positive holding means, will beentirely eliminated. It will also be found that this method of fasteningcorners will produce a frame of extreme rigidity and durability.

It is evident that this process of joining abutting members can beapplied to a wide variety of circumstances. Specific examples can befound in the automobile and airplane fields where tubular or recessedelements are widely used and wherein these elements often must befastened together at a wide range of different angles. This may beexpensive or awkward to hold together by plates or bars which are formedby other processes. My process also has widespread use in temporaryand/or experimental construction in that it provides a quick, accurateand reliable method of forming odd shaped corners and avoids the specialand time consuming work otherwise incident thereto. By this method it islittle, if any, more expensive to construct a storm window for example,for an octagon window than it is to construct a storm window for aconventional rectangular window, whereas under previously known methodsof construction the cost of fitting an octagon window frame was muchgreater than the cost of correspondingly fitting a rectangular frame.

Where this method of preparing corner members is used for connections ofsuch a wide angle, including a straight line (Fig. 6) that the materialwill not collect itself into the corner by gravity as in the situationabove described, it will be necessary to rearrange the mold in someother manner to provide a proper position for setting of the pouredmaterial, such as plugging one end and pouring from the other end. This,however, will be apparent by ordinary casting practice and need not bediscussed here.

This process is also applicable to uses other than the fabrication ofstrictly joining elements. For example, in certain phases of automobileconstruction such members will be useful for aligning elements which areotherwise fastened. The procedure, however, is the same.

Other variations and modifications will be apparent to those acquaintedwith processes and equipment of this sort but all will be within thescope of the following claims except as expressly limited thereby.

I claim:

1. The process of fabricating a window sash corner comprising: utilizingfor said Window sash aluminum sash sections having an opening therein;utilizing as a corner member mold a pair of sections cut from the samestock as the sections from which the sash is to be made, arranging saidmold sections to form a duplicate of the 7 intended corner: and heatingaz-inc alloy melting at approximately 715'F..to a temperature betweenabout 800 and about 850 F. and while at said temperature. pouring. sameinto said mold and then cooling same to. form a corner. member cast ing;removing said casting from the mold sections and inserting it. into.the. corresponding openings of apair. of said sashzsections.

2 The method of fabricating a plurality of constructions. each having acorner, which process method. comprises: utilizing for the elements. ofsaid construction tubular sections having. an internal opening therein,cutting from a current run of such construction sections a pair ofsamples thereof, arranging. said samples to form a duplicate of theintended corner and pouring thereinto a predetermined amount ofliquid-molding material and then solidifying same to form a cornermember casting, removing said casting from the mold sections andinserting it into the respective internal openings of a pair ofconstruction sections to be abutted to form a corner, discardin dsamples and cut ing. from the then current supply of constructionalstock new samples to utilize as mold sections with sufficient frequencyto. maintain :close conformity in size between said castings and theconstructional sections being used at anygiven: time? in spite-ofvariations occurring from time; to time in. the internal dimensions ofsaid tubular constructional Sections. 7

REFERENCES CITED The following references are of record. in the file ofthis patent:

OTHER REFERENCES P. 3;, Cerrobend, pub. by Cerro de Paseoz, CopperCorp., Wall St., New York, N. Y.', May 2;, 1944.

